One of our readers suggested the top right insulator might be a CD 123 E.C.& M. Co. That might be a long shot since I've never even heard of a shard of one of those found anywhere here in the northeast. But anything is possible! And if it is a CD 123 then it could be a Chester N.Y. piece. My thoughts and close observation though inclines me to think it's a CD 127 or CD 127.1 especially since the wire groove is closer to the dome than the CD 123 style. Click "Previous" for more details and for an overall view of this pole and line.